SYNTHESIS AND SOLID-STATE PROPERTIES OF COMB-LIKE IONENES

A series of comb-like ionenes with aliphatic side chains of different length and organic main chain spacer groups of different size have bee n synthesized by the step-growth polymerization of long aliphatic chai n-substituted diamines with alpha,omega-dibromoalkanes. Highly ordered films of layered structure have been obtained by solution casting. Th e long side chains crystallize with an interdigitating hexagonal packi ng perpendicular to the film plane. The perfection of the side chain p acking is related to the size of the spacer group in the main chain as well as to the valence of the counterions, but also depends on the th ermal history of the samples. It is in all cases comparable to the qua lity of aliphatic chain packing in LB multilayers of surfactants. The comb-like ionenes exhibit liquid-crystalline textures above their side chain melting transition.